4106 OTR HVAC Ducting Question

[richard5933]

I finally got the Webasto fired up and running well. Now I'm trying to figure out the way it's ducted to supply hot air inside the coach. This setup uses the Webasto to heat the coolant in a secondary heater core, and then uses low-current squirrel fans to push the heated air inside the coach.

The Webasto is located mid-ship on the driver's side. I've identified a couple of 4" vents that connect directly to the plenum on top of the squirrel fan. There is also air flowing through the OEM floor vents that originally supplied air to the OTR HVAC system on the same side of the coach.

I have not yet found anything from the Webasto installation which would bring the heated air to the curbside of the coach. There are two vents which look like they were installed at the same time as the other Webasto pieces which are connected to the floor ducting on the curbside, but I don't really sense any heated air getting over there.

Here's the question I need help with...In the original OTR heat in a 4106, where is the connection point between the floor ducting on the driver's side and the curbside? Is it in the blower box for the main OTR heater? Or, is it hiding somewhere in the belly of this beast? I assume that they connect somewhere, and I want to examine that connection to see if there is something blocking the heated air from traveling from the driver's side to the curbside. If I can't find the connection point, I may have to wait for a cool day and fire up the Webasto so I can trace the heated air with an infrared heat gun. The squirrel fan doesn't move that much air, so it's hard to tell on airflow alone.

Any thoughts?

Richard

[RJ]

Richard -

You answered your own question: ducting for both sides comes out of the OEM OTR HVAC blower compartment.

FWIW & HTH. . .

[richard5933]

ducting for both sides comes out of the OEM OTR HVAC blower compartment.

That's what I thought. My assumption was that I'd feel air moving out from the vents on both sides of the coach once one side was pressurized. Either I didn't wait long enough or I've got a rat's nest somewhere blocking the works. Keep finding them in the strangest places.

Richard